/Engine/Plugins/FX/Niagara/Source/NiagaraEditor/Public/NiagaraSystemEditorData.h
[UNiagaraScriptVariable](API\Plugins\NiagaraEditor\UNiagaraScriptVariable) * FindOrAddUserScriptVariable ( [FNiagaraVariable](API\Plugins\Niagara\FNiagaraVariable) UserParameter, [UNiagaraSystem](API\Plugins\Niagara\UNiagaraSystem) & System )